Most underwear for small children and in particular those for babies and infants are hitherto formed not of knitted synthesized fiber but of knitted fabric consisting of 100 percent cotton to prevent their soft skins from being stimulated.
That is, undershirts used as top clothes, panties and used as bottom clothes, and coveralls and rompers consisting of the top clothes and the bottom clothes integral therewith are formed by cutting knitted 100 percent cotton into a pattern corresponding to each of the front body, the rear body, and the sleeve and sewing the cut patterns to each other. Mostly, a rubber string is tightly attached to the open end of the sleeve, the lower end of the leg, and the waist part of clothes.
The clothes including underwear consisting of knitted 100 percent cotton lack elasticity and the elasticity cannot be partly changed.
Therefore, the conventional underwear consisting of knitted 100 percent cotton are incapable of following the change in the bodily structure of babies and infants and small children that is made in a great extent because their bodies grow rapidly in a short period of time, thus having a short period of time in use.
Different from adults and children who have reached the school age, babies and infants have a formative feature or a bodily structural feature that they have bellies bulged forward. Underwear and outdoor clothes adapted for this particular feature have not been proposed. In particular, in clothes which consist of a top and bottom portion continuous with each other such as rompers, the part of the clothes corresponding to the bulged belly are required to have a higher degree of elasticity than the other parts thereof in order to achieve conformity to the bulged belly. But the conventional clothes are incapable of doing so and consequently, the part is too large or too small. Thus, the conventional clothes do not fit to the body well.
As described above, babies and infants have bulged bellies, and the formative feature or the bodily structural feature and the actional characteristics are varied greatly depending on growth stages. Thus, it is necessary that the clothes correspond to the formative feature and the actional characteristic of each growth stage but the conventional clothes are not formed in conformity to the change in the formative feature and the actional characteristic. Therefore, the conventional clothes do not fit well to the body of the baby and infant and may obstruct the motion function thereof.
In the case of babies of the first stage, namely, those aged two-four months, the growth speed of the bodies thereof in this stage is faster than any other stage in their lives. The feature of their bodily structure is that they a have long trunk, short legs, and bulged bellies. As the actional characteristic, they lie or turn in their beds and bend and stretch their hands and legs and move their hands and legs while lying on their bellies. Thus, it is most important in their first growth stage to allow clothes to be elastic according to the change in the size of their bulged bellies and allow the clothes to be put on them easily and removed therefrom easily because they keep lying in their beds.
The growth speed of their bodies in the second growth stage, namely, those aged three to eight months from birth becomes slower than that in their first growth stage, but their buttocks become bigger than their bellies. In their actional characteristic, they can turn over in their beds and sit by themselves, i.e., they spend much time sitting. Accordingly, it is important in the second growth stage that clothes are so formed as to correspond to the change in the size of the waist (buttocks) and preferable that the clothes are not loose in the waist part thereof when they sit and are held in the hands of mother or the like.
In the third growth stage, i.e., when they are 6-15 months old, as the formative characteristic, the lower parts of the body grow, and as the actional characteristic, they become active. They can stand by holding something in their hands, stand by themselves or walk by themselves. That is, in the third growth stage, they spend much time standing. Accordingly, in the third stage, it is important that the side of clothes is expansive in conformity to their actions. In particular, the expansion of the part of clothes corresponding to the side of their bodies increases because of their upward motion of their hands and legs. Thus, it is important that the part of the clothes corresponding to the side of their body follows their actions.
As described above, because the growth speed is highest and the formative change is greatest in babies and infants aged 0-15 months throughout their lives, it is desirable that clothes and in particular, underwear can adapt for the their rapid growth and the actional characteristic of each growth stage so that the clothes do not prevent their bodily growth and motion function.
Because small children before school age still have bulged bellies and are very active, it is preferable that clothes correspond to their formative and actional characteristics.
However, as described previously, the conventional clothes for small children including babies and infants are not designed in consideration of their actional characteristics in each growth process. Thus, it can be safely said that the conventional clothes lack the action of developing and accelerating their motion function.
Clothes and underwear in particular for small children including babies and infants are washed frequently. When the conventional underwear consisting of 100 percent cotton are expanded, they are not returned to the original shape, i.e., they become out of shape. Further, the skins of babies and infants are about 1/3 as thick as that of adult's skin and thus are susceptible to stimulus. The conventional underwear have many sewing portions which touch the soft skins of babies and infants and stimulate and roughen the skins.